The present invention relates to a data storage tape cartridge for use with a tape drive as part of a tape drive system. More particularly, it relates to a data storage tape cartridge incorporating a brake body exhibiting high-wear resistant characteristics when engaged by a correspondingly configured tape drive spindle.
Data storage tape cartridges have been used for decades in the computer, audio, and video fields. The data storage tape cartridge continues to be an extremely popular form of recording large volumes of information for subsequent retrieval and use.
A data storage tape cartridge generally consists of an outer shell or housing maintaining at least one tape reel and a length of magnetic storage tape. The storage tape is wrapped about a hub portion of the tape reel and is driven through a defined tape path by a driving system. The tape reel is normally axially aligned with an opening in the housing through which the tape reel can be accessed and engaged by a tape drive chuck. Further, the housing forms a window at a forward portion thereof for allowing access to the storage tape by a read/write head. This interaction between storage tape and head may take place within the housing (for example, with a mid-tape load design), or the storage tape may be directed away from the housing to an adjacent area at which the read/write head is located (for example, with a helical drive design or a leader block design). Where the tape cartridge/drive system is designed to direct the storage tape away from the housing, a single tape reel is normally provided. Conversely, where the tape cartridge/drive system is designed to provide head/storage tape interaction within or very near the housing, a two- or dual-tape reel configuration is typically utilized.
Regardless of the number of tape reels associated with a particular data storage tape cartridge, each tape reel is preferably xe2x80x9clockedxe2x80x9d to the housing when not otherwise engaged by a tape drive. To this end, a brake assembly is provided for each tape reel. The brake assembly can assume a wide variety of forms, such as multiple brake bodies biased to selectively engage an outer circumference of the tape reel. A more common, less expensive approach includes a single brake body and a spring disposed within a central bore of the tape reel. The brake body is normally an integrally formed component, configured to rigidly connect the tape reel to the housing in a locked position. In this regard, the brake body generally defines a housing engagement portion and a tape reel engagement portion. The housing engagement portion is normally slidably connectable to the housing. For example, the housing will include an inwardly extending tab, whereas the housing engagement portion is a stem forming a slot sized to slidably receive the tab. Conversely, the tape reel engagement portion is selectively connectable to the tape reel. Typically, the tape reel engagement portion is a series of teeth sized to engage or mesh with a corresponding toothed portion of the tape reel in the locked position. Finally, the spring is provided to bias the brake body to the locked position.
During use, the brake body must be moved out of the locked position to allow tape reel rotation as a rotatable tape drive chuck engages the tape reel. This is normally accomplished by providing the tape drive chuck with a spindle that contacts and guides the brake body, via a central bore in a tape reel, from the locked position. This area of contact is established between a leading surface (or xe2x80x9cbuttonxe2x80x9d) formed by the brake body and a tip of the spindle. The leading surface of the button is normally generally convex, whereas the spindle tip is flat. Importantly, upon rotation of the drive chuck, and thus the spindle, the brake body remains stationary, with the spindle tip spinning against the brake button. Due to the flat spindle tip and the convex button, the spindle tip/button interface may move from a desired location along the axis of rotation of the spindle.
The above-described two-piece brake assembly design is widely employed. However, certain issues have been identified in conjunction with tape drive system advancements. For example, advancements in tape media, read/write head technology, driving systems, etc., have resulted in tape drive systems able to desirably operate at greatly increased tape speeds. As a point of reference, tape drive system improvements have increased the maximum operational tape speed from about 1 meter per second to speeds in the range of 48 meters per second. This increased tape speed translates to drive chuck rotational rates on the order of 2000 RPM. While the current brake assembly design is highly satisfactory at relatively low tape speeds, potential problems may arise with elevated tape speeds. In particular, the increased rotational rate of the drive spindle against the brake button will rapidly generate a large amount of friction. The friction not only causes brake button deteriorate, but also generates heat that may promote further brake body deterioration, even melting. This highly undesirable result is due not only to brake body material, but also to movement of the brake button/spindle interface from along the axis of rotation of the spindle.
Data storage tape cartridges are important tools used to maintain vast amounts of information. To remain competitive, data storage tape cartridge manufacturers must continually improve cartridge performance while reducing or maintaining overall costs. To this end, currently employed tape reel braking assemblies, and in particular the brake body, will likely fail at higher tape speeds associated with advanced tape drives. Therefore, a need exists for a data storage tape cartridge utilizing a brake body configured to maintain structural integrity at elevated tape drive speeds.
One aspect of the present invention relates to a data storage tape cartridge. The data storage tape cartridge includes a housing, at least one tape reel, a storage tape, a brake body, and a spring. The housing includes first and second housing sections combining to define an enclosure. In this regard, the second housing section forms an opening, whereas the first housing section includes a connector, preferably an inwardly extending tab, opposite the opening. The tape reel defines a central bore and is rotatably disposed within the enclosure such that the bore is axially aligned with the housing opening. The tape reel maintains the storage tape. The brake body is disposed within the central bore of the tape reel and includes a stem, a reel engagement section and a button. The stem is configured to be slidably attached to the connector associated with the first housing section. In one preferred embodiment, where the connector is a tab, the stem forms a slot sized to receive the tab. The reel engagement section is configured to selectively engage a portion of the tape reel in a locked position, preferably in the form of radial teeth. The button is positioned opposite the stem and terminates in a leading end forming a concave surface configured to selectively receive a portion of a rounded surface associated with a tape drive. Finally, the spring is positioned to bias the brake body to the locked position. With the above configuration, the concave surface of the brake body is accessible by a tape drive through the opening in the second housing section and the central bore in the tape reel. Prior to use, the spring biases the brake body to the locked position, whereby the brake body rigidly connects the tape reel to the housing. Upon insertion into a tape drive, a portion of the tape drive, such as a drive spindle, forces the brake body out of the locked position. A rounded surface of the drive spindle, for example a bearing ball, contacts and rotates within the concave surface of the brake body. Due to the unique interface between the drive spindle and brake body, frictional and thermal forces are minimized, even at high tape speeds. In one preferred embodiment, the brake body is integrally formed from a high-heat resistant material.
Another aspect of the present invention relates to a tape drive system comprising a tape drive, a data storage tape cartridge and an engagement assembly. The tape drive includes a motor and a drive chuck. The drive chuck is rotatably driven by the motor and includes an engagement hub and a spindle. The spindle extends axially from the engagement hub and terminates in a tip. The data storage tape cartridge includes a housing, at least one tape reel, a storage tape, a brake body, and a spring. The housing defines an enclosure. The enclosure is accessible through an opening formed in the housing. The tape reel is rotatably disposed within the enclosure and defines a central bore that is axially aligned with the opening. The tape reel maintains the storage tape. The brake body is slidably disposed within the central bore and is configured to rigidly connect the tape reel to the housing in a locked position. Further, the brake body includes a button terminating in leading end forming a concave surface. The brake body is positioned such that the concave surface is accessible via the central bore. The spring is positioned to bias the brake body to the locked position. Finally, the engagement assembly is established between the tip of the spindle and the leading end of the brake body. The engagement assembly includes a rounded surface and a concave surface configured to selectively receive the rounded surface. In one preferred embodiment, the rounded surface is provided by a bearing ball secured to the spindle. In another preferred embodiment, the rounded surface is provided by a bearing ball secured to the brake body. Regardless, during use, the engagement hub engages the tape reel and the rounded surface is received by the concave surface such that the spindle directs the brake body out of the locked position. Upon activation of the motor, the drive chuck rotates the tape reel. In one preferred embodiment, the rounded surface associated with the spindle rotates within the concave surface of the brake button. In another preferred embodiment, the concave surface associated with the spindle rotates about the rounded surface of the brake button. In either case, due to the unique interface between the spindle and the brake body, frictional and thermal forces are minimized, thereby allowing operation of the tape drive at elevated tape speeds without brake body failure.
Yet another aspect of the present invention relates to a method of operating a tape drive system. The method includes providing a tape drive, a data storage tape cartridge and an engagement assembly. The tape drive includes a frame and a drive chuck including an engagement hub and a spindle terminating in a tip. The data storage tape cartridge includes a housing, at least one tape reel, a storage tape and a brake body. The tape reel is rotatably disposed within the housing, and maintains the storage tape. The brake body is configured to selectively connect the tape reel to the housing in a locked position and includes a button terminating in a leading end. The engagement assembly is established between the tip of the spindle and the leading end of the brake body, and includes a rounded surface and a concave surface. The concave surface is configured to selectively receive the rounded surface. The data storage tape cartridge is inserted into the frame. The spindle is directed toward the brake body such that the rounded surface contacts the concave surface. The brake body is then guided from the locked position with further movement of the spindle. The engagement hub then engages the tape reel. The drive chuck is rotated, in turn rotating the tape reel. The brake body remains stationary during tape drive chuck/tape reel rotation. Rotation of the drive spindle is subsequently stopped. Finally, the drive arm is retracted such that the rounded surface disengages the concave surface.
Yet another aspect of present invention relates to a brake body for use with a data storage tape cartridge for selectively rigidly connecting a tape reel to a cartridge housing in a locked position. The brake body includes a stem, a reel engagement section and a button. The stem is configured to slidably engage a portion of the cartridge housing. The reel engagement section is configured to selectively engage a portion of the tape reel in a locked position. Finally, the button is formed opposite the stem and terminates in a leading end forming a concave surface. The concave surface is configured to selectively receive a rounded surface associated with a tape drive, such as a bearing ball captured by a drive spindle.
Yet another aspect of the present invention relates to a data storage tape cartridge. The data storage tape cartridge includes a housing, at least one tape reel, a storage tape, a brake body, and a spring. The housing includes first and second housing sections combining to define an enclosure. In this regard, the second housing section forms an opening, whereas the first section includes a connector, preferably an inwardly extending tab, opposite the opening. The tape reel defines a central bore and is rotatably disposed: within the enclosure such that the bore is axially aligned with the housing opening. The tape reel maintains the storage tape. The brake body is disposed within the central bore of the tape reel and includes a stem, a reel engagement section and a button. The stem is configured to be slidably attached to the connector associated with the first housing section. The reel engagement section is configured to selectively engage a portion of the tape reel in a locked position. The button is positioned opposite the stem and terminates in a leading end. The leading end forms a rounded surface configured to be selectively received by a concave surface associated with the tape drive. Finally, the spring is positioned to bias the brake body to the locked position. With the above configuration, the rounded surface of the brake body is accessible through the opening in the second housing section and the central bore in the tape reel. Upon insertion into a tape drive, a portion of the tape drive, such as a drive spindle, forces the brake body out of the locked position. A concave surface of the drive spindle contacts and rotates about the rounded surface of the brake body. Due to the unique interface between the drive spindle and the brake body, frictional and thermal forces are minimized, even at high tape speeds.